View Code of Problem 3924

#include<stdio.h>
#include<string.h>
char a[10000000];
int main()
{
	scanf("%s",a);
        int len = strlen(a);
		while(i<len){
		while(a[i]==a[i+1])
		i++;
		printf("%c",a[i]);
		i++;
	}
	return 0;
}
/*
Main.c: In function 'main':
Main.c:8:9: error: 'i' undeclared (first use in this function)
   while(i<len){
         ^
Main.c:8:9: note: each undeclared identifier is reported only once for each function it appears in
*/